The purpose of this grant is to request funding for a ThermoQuest Finnigan MAT LCQ Deca Ion Trap Mass Spectrometer (MS). No equipment is currently available for the mass analysis of macromolecules at or within reasonable traveling distance of Dartmouth. All investigators in need of mass analysis of proteins, peptides, oligonucleotides, organometalic compounds and other macromolecules are currently forced to use out-of-house services on an ad hoc basis. The LCQ-MS Deca will be integrated into the Dartmouth College Molecular Biology (MB) Core facility. This facility now offers protein microchemistry, protein sequencing, DNA sequencing and DNA synthesis to 75 laboratories. The MB Core Facility operates under the control of a faculty Director and a faculty Advisory Board. A professional Manager and two support technicians handle day-to-day operations. This facility is a shared resource for the Dartmouth research community, i.e., researchers from the Dartmouth College of Arts & Sciences, Dartmouth Medical School, the Norris Cotton Cancer Center and the Veterans Administration Medical Center in White River Junction, VT. The Dartmouth Medical School and the Dartmouth College of Arts & Sciences have made a substantially commitment to this and other core facilities as part of an institution-wide expansion in the fields of Genetics and Structural Biology. In addition, the College of Arts & Sciences supports the MB Core facility through an NIEHS/EPA Superfund Program Project, and the Norris Cotton Cancer Center continues its support through its NCI Cancer Center Core grant. A major users group for this instrument has been identified consisting of 8 NIH-funded investigators. This group of investigators uses the other services provided by the Molecular Biology Core Facility and expects to use the LCQ Deca MS on the same fee-for- service basis. The major users group currently holds 11 NIH funded research grants totaling $2.8 million in total direct costs annually.